Unable to connect to personal website through modem unless I use VPN -- NOT using Xfinity modem

Starting about 2 weeks ago, I was no longer able to access my personal website via my modem. I can access pretty much the rest of the internet, just not my personal website. I suspect Xfinity is blocking it, since I can access my website:

• via 4G LTE on my phone;
• if I use a VPN through my modem.

Thus, the website is obviously up and working; it only fails when I use Xfinity "in the clear".

I cannot access the website through my modem without VPN, regardless of:

• device,
• browser, or
• operating system.

I found several posts with similar complaints, but the posters all use an Xfinity-supplied modem. I have a Netgear C7000, not Xfinity-supplied.

What should I do to access my website, short of using VPN all the time and/or hoping that someone else finally breaks Xfinity's monopoly on high-speed internet in my area?

I don't know if this is related, but the xfinitywifi hotspots in my area don't seem to be working.

In case it helps clarify, here are some things Xfinity support has told me to do over the last two weeks, along with the results.

• Various problems related to their determination to blame my modem.
  • Turn my modem off, then back on.
  • Check my modem settings to verify it wasn't blocking the website.
  • Reset my modem.
    • I even performed a factory reset.
  • I'm reasonably sure at this point the problem isn't my modem.
• Visit https://downforeveryoneorjustme.com/ . "It's just you."
• Visit a site to test my IPv6 connectivity. "10/10"
• Use a different browser.
• Use a different device.